Forty years ago Friday, President Richard Nixon declared a “war on cancer.” And while no one would think of declaring victory, it’s rarely discussed how successful that war has been. Thanks to advances in screening, diagnosis and treatment, more people are alive today after beating cancer than ever before.

Seven-time Tour de France winner Lance Armstrong conquered testicular cancer in 1996. “Dexter” actor Michael C. Hall has been in remission from Hodgkin’s lymphoma for a year. E! host Giuliana Rancic is recovering from a double mastectomy performed this month, and Christina Applegate has been cancer free since her double mastectomy in 2008.

Cancer still claims 1,500 people a day. But in an increasing number of cases, it is evolving into a chronic disease, rather than a fatal one. In 1971, there were only 3 million cancer survivors in the US; today there are 12 million, and the number keeps growing.

In the mid-1970s, only 50% of people diagnosed with cancer lived five years. Today, it’s 68%, and much higher for certain forms of the disease, such as prostate cancer.

“When I started in this field 30 years ago, we were helping people die of cancer. Now it’s a question of living with the disease, embracing the future,” said Julia Rowland, director of the National Cancer Institute’s Office of Cancer Survivorship.

FIRST RESPONDERS

One of the primary reasons for the success is that doctors have gotten much, much better at finding the disease. The earlier cancer is caught, the easier it is to beat, and an increased awareness about such screenings as mammographies, Pap tests and colonoscopies have helped turn the tide.

Steady declines in breast cancer deaths are largely attributed to mammography, which detects about 80%-90% of breast cancers in women without symptoms. And colorectal-cancer screening has led to a decrease in cancers and a decline in cancer deaths.

Even heavy smokers are breathing sighs of relief thanks to improved screening techniques. One clinical trial found CT scans could detect earlier stage cancers in people who smoked a pack a day for 30 years, resulting in 20% fewer lung-cancer deaths in this high-risk group.

More than half of all cancer cases occur in people 65 or older, and as baby boomers age, doctors are bracing themselves for an onslaught. The National Cancer Institute estimates that there will be a 42% increase in the number of cancer survivors 65 or older between 2010 and 2020.

There is some hope, however: Baby boomers tend to be healthier than their predecessors, and are more likely to get screened early and to seek treatments at earlier stages.

“It’s a generation that wants to have information and is empowered, and we hope that means early screening,” Rowland said.

Some cancers, such as pancreatic cancer, don’t lend themselves to screening — yet. They are insidious diseases that develop with virtually no symptoms, Pancreatic-cancer patients’ only clue is usually jaundice, but that only develops after the disease has spread to the liver and other tissues. Fewer than 5% of pancreatic-cancer patients survive five years after diagnosis.

Researchers at the Johns Hopkins Medical Institutions are developing a blood test they hope will find a common form of pancreatic cancer decades before it becomes deadly.

“The dream is that you walk into your physician’s office at your yearly checkup and get a blood test and that blood test can tell you whether you have pancreatic cancer,” said Dr. Bert Vogelstein, a lead researcher at Johns Hopkins.

“Almost everybody who dies of pancreatic cancer only dies because their cancer wasn’t detectable in the first decade or two of its existence,” Vogelstein said. “Hopefully, if it’s detected prior to symptoms, it can be removed surgically.”

In this way, Steve Jobs is a lesson in opposition. According to his biographer, Jobs’ disease was one of the rare pancreatic cancers detected early enough to be removed surgically. Had the Apple co-founder undergone the recommended surgical treatment right away, he might have lived a little longer. Instead, he put off surgery, trusting in alternative treatments for nine months, by which time the cancer had spread.

KILLING IT SOFTLY

Jobs was not alone in balking at cancer treatments. Chemotherapy, radiation and other treatments are still largely harsh and barbaric — killing healthy cells as well as cancerous ones. But, increasingly, oncologists are finding less toxic, more targeted therapies.

The American Society of Clinical Oncology picked its Top 5 advances in cancer care for 2011 this month. Leading the list were targeted drugs that attack hard-to-beat tumors with fewer side effects, such as Zelboraf, which goes after a key gene mutation in melanoma, and Xalkori, which shrank half the tumors of advanced non-small-cell lung-cancer patients who had a specific gene mutation.

A better understanding of the genetics of particular cancers allows researchers to develop medicines like these that target key parts of the tumor cells, making therapies more specific and effective.

“The old story of chemotherapy is going away — this is no longer your grandfather’s Buick. These are pills that make cancer a truly manageable disease, much like diabetes,” Dr. Nicholas Vogelzang, head of the section of genitourinary cancer at the Nevada Cancer Institute in Las Vegas and co-executive editor of the report, told reporters this month.

Oncologists are also using an understanding of genetics to determine who would benefit from certain treatments.

“Chemotherapy doesn’t work in everybody, so we’ve begun to use fancy genetic tests to see who gets a benefit from chemotherapy,” said Clifford Hudis, chief of breast-cancer medicine service at the Memorial Sloan-Kettering Cancer Center. “We spare the toxicity for a large group of people.”

Doctors are increasingly adding to their arsenal immunotherapy and “treatment vaccines,” drugs that use the body’s own immune system to target cancer. Most notably, the drug Herceptin has been used for more than a decade in breast-cancer patients — a move that cut the death rate from the disease down by about a third, Hudis said.

Unlike prophylactic vaccines, which are given to prevent disease, treatment vaccines are used in people who are already sick. The vaccine introduces antigens into the body, usually by injection, which activates antibody-producing B cells and killer T cells and directs them to attack cancer. An antigen can be a protein or another type of molecule found on or in a cell and usually causes minimal, if any, side effects.

In the US, a small handful of treatment vaccines are being used in fighting prostate and other cancers, with more being tested.

In Israel, researchers have begun clinical trials on a treatment vaccine, called ImMucin, they believe will battle 90% of all cancers. The treatment works by “teaching” a cancer patient’s T cells to target a specific protein that is made by most cancer cells, including breast, lung, ovarian, colon, prostate and pancreatic cancers.

About 15 people battling the blood -cancer multiple myeloma are enrolled in the study in Israel, but there are plans to expand the trial to the US, said Dr. Lior Carmon, founder and CEO of Vaxil BioTherapeutics, which designed the vaccine.

“One of the very positive things about therapeutic vaccines is that they can work as a stand-alone treatment or in combination with other treatments,” Carmon said. “The treatment is usually a course of injections over a period of a few months, followed by vaccination at lesser frequency for maintenance.”

Among the immunotherapies currently available here, the FDA recently approved Yervoy for patients with previously untreated metastatic melanoma. The drug activates the patient’s immune response and, when combined with standard chemotherapy, extended life by two months. This may not seem like a huge gain, but it’s a step in the right direction, oncologists said.

“The extension of lives may be modest, [but] we need to appreciate that they are real,” Dr. Len Lichtenfeld, deputy chief medical officer for the American Cancer Society, told reporters. “Ten years ago, we started talking about making cancer a ‘chronic disease,’ and we are starting to see that happen.”

A POUND OF CURE

The best way to beat cancer is to not get it in the first place, and researchers are growing increasingly confident that this will be possible.

“The history of medical research shows almost all major decreases in morbidity are due to preventative measures, as opposed to trying to cure the disease,” Vogelstein said. “If you’re thinking about it broadly, what are you going to try to do? Are you going to try to prevent polio or cure polio?”

Vogelstein hopes that cancer funding will eventually skew more heavily toward developing effective cancer preventions. In some areas, that is already happening.

Two vaccines against the human papillomavirus are powerful protectors against cervical cancer — as nearly all cases of the disease are associated with HPV.

In some cases, doctors have found success in giving breast-cancer treatments to women who don’t have the disease. Researchers discovered that the drug Aromasin “starves” breast tumors by blocking the enzyme aromatase, which is responsible for converting androgen hormones to estrogen. The drug has reduced the risk of developing breast cancer in postmenopausal women at high risk for the disease. Unfortunately, aromatase inhibitors have some nasty side effects, including severe joint pain, reduced libido and hot flashes — and many women quit the treatment rather than suffer these problems.

While science is getting better at developing preventions and addressing side effects, researchers are quick to point out that some of the best prevention methods come in the form of a stick of gum and a pair of running shoes. Smoking is responsible for an estimated 171,600 cancer deaths this year alone, and one-third of all cancer deaths this year were related to obesity, lack of exercise and poor nutrition.

“Obesity is the most rapidly increasing problem that we face,” Hudis said. “When people ask, ‘Why can’t we do more about prevention?’ The first thing that most people need to do is eat less food.”